メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.6937500 37.0916667, 138.7000000 37.0916667, 138.7000000 37.0958334, 138.6937500 37.0958334, 138.6937500 37.0916667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral